In this story: 'Put this information in context' 'Controlled descent' RELATED STORIES, SITES

November 11, 1999
Web posted at: 12:03 p.m. EDT (1603 GMT)

NEWPORT, Rhode Island (CNN) -- The ocean floor search for the cockpit voice recorder from EgyptAir Flight 990 was suspended Thursday because of worsening weather at the crash site. Investigators say they need that second "black box" to solve mysteries left after analysis of the plane's flight data recorder.

VIDEO Watch the NTSB news conference on preliminary information from EgyptAir Flight 990's data recorder QuickTime Play Real 28K 80K Windows Media 28K 80K CNN's Carl Rochelle reports on the recovery of the flight data recorder QuickTime Play Real 28K 80K Windows Media 28K 80K     HOTLINES EgyptAir information lines: In the U.S.: (800) 243-1094 Outside the U.S.: (202) 245-2244 (202) 244-1460 (202) 418-3690 FBI Information line: 1-800-473-4761     MESSAGE BOARD Plane crashes     ALSO Depth comparison of various crashes Roller coaster ride of EgyptAir 990 disputed by experts Passengers and crew on EgyptAir Flight 990

Deteriorating weather forced authorities to order the flotilla of ships searching for the cockpit voice recorder back to port. "The seas are too high for anything to go on," said U.S. Navy Petty Officer Terry Burnley.

Burnley said several ships worked into the early morning hours of Thursday before being called back to shore because of high waves amid generally worsening weather conditions near where the plane went down in the Atlantic.

Burnley said the submarine support ship Carolyn Chouest, a civilian vessel under contract to the Navy, pulled its submersible robot from the ocean at about 5:30 a.m. He said the Navy rescue and salvage ship USS Grapple, the Coast Guard ship Juniper and the ocean-going tug Mohawk also were ordered back to port.

Two remote-controlled underwater robots, Deep Drone and Magnum, are being used in the search amid rubble piled 6 feet high, some 250 feet below the ocean surface.

The flight data recorder, recovered Tuesday, shows things were normal on the Boeing 767 until the autopilot mysteriously disconnected.

"We await information off the cockpit voice recorder, when it is recovered, that can help us put this information in context," Jim Hall, chairman of the National Transportation Safety Board, said Wednesday as he revealed the first bits of information from the plane's flight data recorder.

The voice recorder may not only reveal what the pilots were saying to each other, but what other noises or alarms were audible in the cockpit.

In Boeing airplanes, for example, an alarm sounds if the autopilot disconnect button isn't pressed twice in a row -- a way to prevent the pilots from missing an accidental disengagement.

Hall said the New York-to-Cairo flight had been cruising normally at 33,000 feet when the autopilot disconnected. That is unusual, because the plane was just beginning its hours-long cruise across the Atlantic Ocean. Hall refused to say if the autopilot disconnected manually or automatically.

About eight seconds later, the flight "begins what appears to be a controlled descent" from 33,000 feet to about 19,000 feet, Hall said.

The recorder stopped shortly afterward, and the final five to 10 seconds of information on its tape are still being extracted by safety board technicians. Without that information -- details from the cockpit tape or more analysis of radar data showing that the plane later climbed briefly before plunging to the ocean -- investigators will have difficulty explaining the crash.

Hall dashed speculation that the plane's initial plunge was caused by a problem with a thrust reverser -- the cause of a 1991 crash of another Boeing 767 in Thailand.

Thrust reversers are used to slow an airplane upon touchdown with the runway. One of EgyptAir's reversers was out of service at the time of the crash.

"There is no evidence of thrust reverser deployment in the data we have," Hall said.

Investigators have not ruled out any possible cause, including mechanical failure, human error, sabotage and terrorism.

The flight data recorder was designed to capture over 150 types of information from 55 aircraft systems during a rolling 25-hour period.

Among them were such things as the plane's altitude, speed, spin and roll, when electrical power was cut off, and how the autopilot functioned.

Hall said the recorder showed that the plane did not hit supersonic speed in its initial descent.

He did not comment on how the airplane behaved after a brief climb shown by radar data, or in its final plunge to the ocean, which also was tracked on radar.

Hall did not mention the FBI, which likely would be involved if analysts suspect any criminal activity. The FBI continues to monitor the investigation.

Note: Pages will open in a new browser window

External sites are not endorsed by CNN Interactive.